Analyze serum samples, eluates, and biopsies from human kidney tissue in potential transplantation patients to identify antibodies present in diseased glomeruli and tubules. Define antigen-antibody systems involved in the genesis of glomerulo-nephritis and tubular-nephritis, and identify etiologic events which trigger immune resposes leading to these nephritides. Study serial renal biopsy specimens on patients before, during, and after transplantation in an effort to determine whether the renal failure in transplants is due to a recurrence of the original disease. Compare and evaluate tests for detection of serum antiglomerular basement membrane antibodies. Further evaluate the significance of anti-GBM antibodies in ALG preparations currently used clinically to nullify rejection. Expand the search for any microbial agents of chronic human glomerulonephritis and the elucidation of the nature of antibodies and antigens involved in circulating immune complex nephritis by employing a panel (10) of human chronic viral agents' antisera.